Dunlop's pieces are good, but not quite what I'm looking for, as they discuss a lot of concepts (playability, aesthetics, etc.) that I don't want to take on (yet). I'm looking for something short and sweet that talks about how turf quality can be negatively affected by too many trees because of sunlight and airflow issues. I have an audience that might be receptive at the moment because of our turf issues, and so I'd like something that addresses that issue only.